In recent years, in terms of an increase in the size of a liquid crystal display screen and an improvement of operability, radio communication apparatuses such as cellular phones in which a display-side casing including a display screen and an operation-side casing including operation keys are slid relatively so that the radio communication apparatuses are opened and closed have been increasing.
There are known slide-type radio communication apparatuses in which antenna characteristics may deteriorate depending on a positional relation between a display-side casing and an operation-side casing. Accordingly, various technologies have been developed to maintain desired antenna characteristics.
As such a kind of technology, a portable radio terminal apparatus described below is disclosed in Patent Document 1 (Japanese Laid-open patent publication NO. 2006-197292). In the portable radio terminal apparatus, a short stub is provided in a space between an upper ground included in a display-side casing and a lower ground included in an operation-side casing. Since the short stub is coupled with the upper ground that has an adverse effect on an antenna device when the portable ratio terminal apparatus is opened in a slide manner, the deterioration in the antenna characteristics can be reduced.